Almost every passenger-vehicle comes equipped with a rear-view mirror. The driver may often need to look at the rear-side of the vehicle through this mirror, and is an integral part of driving. While driving, many a times the driver gets blinded by the light reflected through these mirrors. The primary line of vision faces the front whereas the bright light from the rear view mirrors hit the eye at peripheral areas. It has been observed that glancing into the rear view mirrors while such lights are being reflected, causes hyper-polarization and hence straight line driving gets obstructed. Such harsh stimuli caused by the lights reflected from the rear-view mirror results in irritation and lack of response of the eye.
Various technologies have been used to control light from rear-view mirrors, that is, the Left, Centre, or Right mirrors, with varying degrees of success. The systems and methods known in the art approach this problem by using photosensitive materials, such as, electro-chromic glass, using chemical means to achieve dimming of bright lights passed through. Such system averages the light intensity on the entire viewing surface, and therefore results in poor detail in the shadows.
Recently, back-up or parking assist displays have been adopted that provide a video image of a scene of the rear of the vehicle to the driver, where the driver's view may otherwise be obstructed. This is a significant safety feature insofar as it helps to eliminate the chance of driver backing up over an object right behind the vehicle. However, these camera based rear-view mirrors have the limitation that any light hitting the mounted cameras makes the ultra-sensitive averaging CMOS sensor top out, which cause white-blotting in the screens in front of the driver. Hence, their use is restricted only to reversing applications, where wide-mode cameras are used and light controlled by ‘not looking’, or ‘waiting for the offending vehicle to move’, to avoid glare.
EP Patent Number 2378350 provides a rearview assembly for a vehicle that includes a housing, a video display positioned in the housing for generating a polarized display image, and a depolarizing device positioned in front of the video display for depolarizing the polarized display image. The intensity of display may be controlled using a glare sensor configured to sense light levels falling on display which may be excessive relative to the prevailing ambient light condition. The intensity of display may be increased from the otherwise normal level when these conditions are present to prevent washout.
In such back-up assist display, the mirror acts in one of two modes: a normal mode and a glare reduction mode; and transitions between one mode and another mode based on the signal from the glare sensor. Such assembly employs a processor system that produces ‘enhanced glare free’ image. The digital processing required to achieve that in the processor system may be very high, and therefore may increase the overall cost of the assembly. Further, such mirrors offer two different perspectives depending on the eye (Left or Right) and any ‘opacity blocking’ attempted will create huge hindrance for the other eye, especially since the area of the mirror is small.
Therefore, there is a need of a device which may help to reduce glare without loss of any details. Specifically, there is a need of a system that enables to spatially and selectively process the incoming light for reducing glare, and thus provide better control over the visibility over the viewing surface.